It's funny how it is with families: When you're apart, you miss 'em. Can't wait to see 'em. Long to be with 'em.

And when you finally do get together, it's great.

For 30 minutes.

Inevitably those flaws and foibles you've conveniently forgotten creep to the surface. Silly squabbles erupt. Every dis and dysfunction begins to work your last nerve.

You can't wait to get away.

So it is with the Wilson/Sims family, whose lives are revealed in microscopic detail in the much-publicized 10-hour documentary series "An American Love Story," which airs tomorrow at 9 p.m. on WETA and continues at the same time for the next four nights. The documentary is a blend of cinema-verite eavesdropping, voice-overs, interviews, still photos and original music, culled from more than 1,000 hours of footage that award-winning documentary filmmaker Jennifer Fox shot of the family over an 18-month span.

At first, watching the way members of this interracial family from Queens, N.Y., navigate through their world makes for good television. They enchant and intrigue. But somewhere around the fourth or fifth episode, they start to wear out their welcome.

Notwithstanding the hype--the accompanying Web site, the soundtrack CD and the CD of Bill Sims's music--they're basically an ordinary family with more or less ordinary problems. Which means that after a while, you really, really, really want them to go home. Except that they are home, because you're basically a fly on the walls of their cramped, smoke-filled, two-bedroom apartment.

Of course, this isn't the first time that a family welcomed a crew of filmmakers to eavesdrop on everyone's life. In the 1970s, the Louds did it, unraveling famously in the landmark series "An American Family." MTV watchers check in regularly for the not-so-real "Real World," where Gen-X'ers actually audition for the chance to have their lives videotaped. And "Frontline" producer June Cross explored her own interracial family's troubled past in the documentary "Secret Daughter."

"An American Love Story" is almost embarrassingly intimate as it digs and digs--past the superficiality of race, past the make-nice facade we all present to the outside world--to reveal the warts and pettiness of family life and, ultimately, the surprising tenacity of love.

We first see the family as daughters Cicily and Chaney prepare a surprise anniversary dinner for their parents. Sims and Karen Wilson cuddle and coo, slow-dancing and gushing about till death do us part. They're a loving couple, together since '67, married since '79. They've got a mortgage to pay, bills to juggle and kids to raise.

Real life, real challenges. Throw race into the mix and you complicate things: Karen, a corporate manager, is white; Bill, a blues musician, is black. Karen works a day job; Bill stays home and cooks. College student Cicily and pubescent Chaney walk a biracial tightrope.

"People think my family's weird," one of the daughters says in a voice-over. "People don't understand why they're together. If they didn't love each other, it wouldn't last."

That they love each other is never in doubt. They've created a cocoon where the opinions of outsiders are of no matter. Indeed, Karen and Bill, natives of working-class Ohio, encountered incredible opposition to their relationship: fury from family and friends, police harassment of Bill, folks poisoning their dog and torching their car. Through it all they've clung together, sharing laughs, hugs and cigarettes.

As Bill puts it: "Family's the most important thing. Everyone else is just an acquaintance. You can't trust anyone else but your family."

Still, there are problems, serious problems. Bill, a stoic, lanky man with a rumbling bass of a voice, has a drinking problem. Sometimes he stays out nights and doesn't come home. He's got two kids from another relationship, including a son who is facing jail time. Karen, an introverted woman who loves her kids with a fierceness, is seriously ill and needs major surgery. Cicily, traveling to Nigeria on a school trip, is ostracized by African American students because she won't choose racial sides.

They face crises that have undone many a family. Somehow, they manage to keep it together. Through the day-by-day process of growing a family, race is transcended. It becomes an afterthought, both for the Wilson-Sims clan and the viewer. Which is exactly what the filmmaker intended.

For all its length, "An American Love Story" leaves unanswered questions: Why did Karen and Bill wait so long--six years after Cicily was born--to marry? Why do Cicily and Chaney have different last names?

On Cicily's African trip, half the students are black; the others white. One other student is also of mixed race. Yet this student is never seen or heard from. Given the difficulties that Cicily encounters on her trip, this is a serious gap.

To watch "An American Love Story" requires serious commitment--a commitment the viewer might question during the course of this marathon viewing. Still, long after the last credits roll over the black-and-white family photos, the Wilson-Sims family manages to stick around, rattling around in the psyche. Like your own family, these people irritate you to no end. Despite this, you do care about them--even though you wish that, just once, they'd keep their visit short.